1. Field of the Invention
The present invention relates to a machine for renewing a railroad track on a ballast bed, which comprises a machine frame extending in a longitudinal direction, undercarriages for supporting the machine frame on the railroad track, a first tie transport device for receiving old ties and a second tie transport device for laying new ties, the tie transport devices being mounted on the machine frame and being spaced from each other in the longitudinal direction, and a crawler vehicle and ballast bed planing apparatus arranged on the machine frame between the tie transport devices.
2. Description of the Prior Art
Such a machine, which may be operated in opposite driving directions, is disclosed in U.S. Pat. No. 5,357,867. In one driving direction, an old railroad track is renewed while a new railroad track is laid on a prepared planed surface in the opposite driving direction. During a track renewal operation, the machine is driven while supported by a crawler vehicle on a planed renewal track section from which the old track ties and rails have been removed, a ballast planing apparatus preceding the crawler vehicle in the driving direction for planing the ballast. The new track is laid on the planed ballast bed behind the crawler vehicle. For this purpose, the machine is driven in the opposite direction and must be retrofitted by mounting the crawler vehicle on the machine frame in front of the device for laying the new ties, in respect of the opposite driving direction. In addition, the tie elevator for laying the new ties is turned around while the tie transport device for receiving the old ties and the ballast planing apparatus are raised into an inoperative position.
It is the primary object of this invention to provide a railroad track renewal machine of the above-described type, which requires minimal retrofitting when driven in opposite directions.
The above and other objects are accomplished according to the invention with such a machine wherein the ballast bed planing apparatus is rotatable by 180xc2x0 about a vertical axis.
Such a machine may be operated in opposite driving directions during a track renewal operation without any substantial retrofitting. This may be of considerable advantage, for example, when a double track is to be renewed. In this case, the machine may work back in the opposite direction on the other rail after one rail has been renewed, without having to engage in complicated and time-consuming retrofitting needed to turn the entire machine around. It is also advantageous to be able to drive from either side towards the renewal site to start the track renewal operation, depending on the prevailing conditions and without having to take into consideration the orientation of the machine. The ballast bed planing apparatus may always be rapidly and readily turned in the driving direction to be in the proper operating position for planing the ballast.